Synthesis of Fatty Acid Methyl Ester from Croton macrostachyus (Bisana) Kernel Oil: Parameter Optimization, Engine Performance, and Emission Characteristics for Croton macrostachyus Kernel Oil Fatty Acid Methyl Ester Blend with Mineral Diesel Fuel

Utilization of agricultural waste such as nonedible seed oil for the synthesis of biodiesel via catalytic transesterification is one of the effective ways for the partial replacement of petroleum-based fuels in the area of renewable energy development and is beneficial to CO, CO₂, and unburned hydrocarbon (HC) emission reduction to the environment. In this regard, the current study investigates the synthesis of fatty acid methyl esters (FAMEs) from Croton macrostachyus kernel oil by considering parameter interaction and optimization to maximize the yield of fatty acid methyl esters (FAMEs). The response surface methodology-central composite design (RSM-CCD) was applied to optimize the C. macrostachyus fatty acid methyl ester (CMKO-FAME) synthesis process by varying the process parameters such as reaction time (1-2 h), molar ratio (6:1-12:1), and catalyst loading (1-2 wt %). The optimum conditions for the transesterification of C. macrostachyus kernel oil (CMKO) were found to be a methanol to oil ratio of 11.98:1, catalyst loading of 1.03 wt %, and reaction time of 2 h, resulting in the conversion of 95.03 wt % C. macrostachyus kernel oil into its mono FAMEs. The fuel properties of CMKO and its FAMEs were determined based on ASTM D6751 and EN 14214 standards. Further, the CMKO and its FAMEs were characterized using Fourier transform infrared (FT-IR), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance spectroscopy (NMR). The fatty acid composition of CMKO was myristic acid (1.36%), palmitic acid (11.35%), stearic acid (5.11%), oleic acid (18.64%), gadoleic acid (0.34%), linoleic acid (49.084%), and linolenic acid (14.1%). The purity of the produced methyl esters was determined by ¹H NMR and found to be 95.52%, which was quite in good agreement with the experimentally observed yield of 95.39 wt %. The produced CMKO-FAME was blended with diesel fuel at various ratios (B5, B10, B15, and B20) to evaluate the engine performance and emission characteristics in a diesel engine. The engine brake thermal efficiency is lower, the brake-specific fuel consumption (BSFC) using CMKO-FAME blends is higher, and the temperature of exhaust gas emitted after combustion also increased as compared to diesel fuel. Similarly, using produced FAME blends, the emission emitted such as HC, NOx, and CO is reduced. However, the engine fueled with the produced FAME blends increased the level of CO₂ into the atmosphere when compared to diesel fuel. The performance and emission characteristics of diesel engine result show that the blend of CMKO-FAME and diesel can be used as a fuel in a diesel engine without any modification of the engine.

Preparation of solid acid catalysts from waste biomass and their application for microwave-assisted biodiesel production from waste palm oil

Waste utilization is essential and challenging. Utilization of wastes gives environmental, economic, and social benefits. In this study, inexpensive, sulfonated solid acid catalysts were successfully prepared from palm empty fruit bunch (PEFB), coconut meal residue (CMR), and coconut coir husk (CH) waste by a simple protocol. It was found that prepared PEFB-BCS-SO₃H, CMR-BCS-SO₃H, and CH-BCS-SO₃H catalysts have 4.79, 3.75, and 2.80 mmol g^-1 acid density and 739.0, 89.77, and 61.49 m² g^-1 surface areas, respectively. Further, the presence of active functional groups on the surface of the catalysts was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Thermal stability of the catalysts was found below 150°C. Results show that biodiesel yield increases with increasing reaction time and methanol loading, when using microwave heating for biodiesel production from waste palm oil (WPO) and prepared catalysts. A maximum biodiesel yield of 95.5% was obtained by PEFB-BCS-SO₃H in 60 minutes using 20:1 methanol:oil (molar ratio) at 70°C. CMR-BCS-SO₃H and CH-BCS-SO₃H obtained 88.7 and 88.5% biodiesel yields in 60 minutes, using 20:1 and 16:1 methanol:oil (molar ratio), at 70 and 110°C, respectively. Even though, the activity of the catalysts decreased during reuse, these are still of interest as the waste biomass of PEFB, CMR, and CH can be used for catalyst preparation and microwave-assisted biodiesel production from WPO.

Sustainable utilization of waste palm oil and sulfonated carbon catalyst derived from coconut meal residue for biodiesel production

In this study, an inexpensive, environmental benign acid catalyst is prepared using coconut meal residue (CMR) and employed for biodiesel production from waste palm oil (WPO). The total acid density of the catalyst is found to be 3.8mmolg^-1. The catalyst shows a unique amorphous structure with 1.33m²g^-1 of surface area and 0.31cm³g^-1 of mean pore volume. Successful activation is confirmed by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The highest biodiesel yield of 92.7% was obtained from WPO in an open reflux system using the catalyst. Results show that biodiesel yield increases with increasing methanol:oil (molar ratio) and reaction time up to an optimum value. It is found that the catalyst can be reused for at least four cycles for >80% biodiesel yield. Fuel properties of the produced biodiesel meet international biodiesel standards.

Nano-ZrO2 sulfuric acid: a heterogeneous solid acid nano catalyst for Biginelli reaction under solvent free conditions

Nano-ZrO₂ sulfuric acid [n-ZrO₂–SO₃H (n-ZrSA)] has been synthesized from the reaction of nano-ZrO₂ with chlorosulfonic acid as sulfonating agent.

Ultrasonic-assisted biodiesel production from waste cooking oil over novel sulfonic functionalized carbon spheres derived from cyclodextrin via one-step: a way to produce biodiesel at short reaction time

A novel sulfonated carbon derived from cyclodextrin showed high catalytic activity for the ultrasonic-assisted transesterification of waste cooking oil.